The invention is based on a fuel injection nozzle for internal combustion engines. Injection nozzles of this kind are distinguished by the fact that the downstream section of the fuel conduit adjoining the valve seat, which serves to effect further fuel preparation and formation of the injection stream, can be embodied and dimensioned with relative freedom of choice, without being hindered by a closing member, and furthermore by the fact that the fuel is carried all the way through the chamber intended for the disposition of the closing spring, so that no particular provisions have to be made for preventing or eliminating leaking oil from the cylinders. These injection nozzles thus combine the advantages of nozzles having an inwardly opening valve needle (called I-nozzles) with those of nozzles having an outwardly opening valve needle (A-nozzles), yet they do not have the disadvantages of either type.
In the known injection nozzles of the general type discussed above, the hollow needle is supported in the closing position on the valve needle via the valve seat, while the valve needle in turn rests on a shoulder attached to the housing. In order to restrain the valve needle with respect to the hollow needle as the hollow needle moves in the opening direction, the valve needle is pressed by a spring against the shoulder attached to the housing. In this known embodiment, the valve seat is stressed relatively severely, and furthermore, when the valve is in the open position, a precise position of the valve needle with respect to the hollow needle is not assured, because the valve needle is held against the stop attached to the housing only by tensional engagement. It also appears to be disadvantageous that the bearing gap between the hollow needle and the nozzle body, in the closing position of the valve, is not shielded from the combustion chamber of the engine, so that the ability of the hollow needle to slide may become impaired over the course of time.